Avalanche Forecast

After a cool start, strong late April sunshine and rising freezing levels will quickly increase the loose wet hazard on all solar aspects. If the alpine winds out of the E-SE and high clouds increase in the afternoon as forecast, the greatest loose wet hazard above treeline will likely peak late morning through early afternoon. Fresh snow near and above tree-line will quickly activate with a natural shed cycle likely on steeper solar slopes. Loose wet avalanches at lower elevation may be less likely to initiate naturally, but if skier triggered, could entrain older snow layers and become large in specific areas. Keep this in mind around terrain traps. 

Winds have transported recent snowfall over the past week onto lee slopes, with the most snowfall and transport occurring above treeline. Be suspicious of steeper wind loaded slopes below ridges. Expect the wind slab hazard to increase quickly with elevation. Wind slabs may be the largest and most sensitive in the Mt Baker area above treeline. 

Cornices are still large so give them a wide safety margin. Natural cornice releases and resulting slab avalanches are dangerous and unpredictable. Give cornices a wide berth if traveling along ridge-lines and avoid slopes below large cornices. See a blog post regarding cornices here.

Avoid unsupported slopes with overhanging blocks of snow and smooth rock underneath. Glide avalanches can release at any time, not just during the heat of the day, and are by definition difficult to predict and manage. 

The active weather pattern continues into late April for the Pacific Northwest despite what the calendar says. Over the last few days, Mt. Baker has picked up about 3 inches of water equivalent (WE) while other areas along the west slopes have picked up 1 - 1.5 inches of WE. Much or all of this has fallen as snow above 5000 feet in the north and 5500-6000 feet in the central and south Washington Cascades. Natural loose wet avalanches have likely occurred throughout the week as the snow-line has oscillated or on solar aspects at lower elevations during sunbreaks. 

Recent observations

The Chinook Pass DOT on Tuesday reported loose wet avalanches entraining older snow below 5000' on steeper slopes.  Wednesday was cooler and cloudier with less avalanche activity. 

NWAC pro-observer Lee Lazzara was in the Mt. Baker backcountry on Wednesday. Lee found recent wind slab on lee slopes near and just above 5000' up to 30 cm thick but unreactive in ski or snowpack tests. Lee observed a large recent glide avalanche on Mt. Herman (see Lee's Instagram post) as well as evidence of a recent loose wet cycle from earlier in the week.